I'm afraid I can't be much help with this problem, and I don't envy you going through it at your age...my more obvious problems built up over the years so I got through all the "meet, greet and impress" parts of my social life while I was still relatively healthy, without outward signs of illness. I did manage to interview for and get a new therapist/technician job following a stroke, and I was very "upfront" about it on my application, but quick to point out that the causes were well controlled by that time, and I had no residual damage.
Now, when I meet new people, I don't bring health issues up unless they do. If I'm feeling unwell (now there's a nice simple understatement!) I simply excuse myself and leave the situation. I don't often put myself in social situations anyway, but when I have to, I make sure I have an "out"...for example when we attended a family wedding last fall, I booked a room at the hotel where the reception was even though it wasn't far from home. That way my husband could enjoy all the festivities while I slipped away to rest.
One thing I've had a personal problem with is that I often assume that people see my absences, non-physicality, or limitations, as laziness and antisocial behaviour, and I tend to respond to my perception of their reaction, without waiting for them to actually respond. That isn't fair to the other person, and I'm working on it. by expecting others to not judge me fairly, I've been unfair to them! I suppose the psychologists among us will interpret that as feelings of guilt about my illness, but I'm working on that, too!
My only advise would be to try to see yourself as a person who happens to have SjS (or other chronic illness)...not as a SjS patient! The person has to come first, the illness is only a part of that.